lkml.org 
[lkml]   [2023]   [Mar]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v7 2/4] mm: Introduce memblock_isolate_memory
From

On 3/12/23 10:35, Mike Rapoport wrote:
> Hi Alexandre,
>
> On Fri, Mar 10, 2023 at 10:45:37AM +0100, Alexandre Ghiti wrote:
>> This function allows to split a region in memblock.memory and will be
>> useful when setting up the linear mapping with STRICT_KERNEL_RWX: it
>> allows to isolate the kernel text/rodata and then avoid to map those
>> regions with a PUD/P4D/PGD.
>>
>> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
>> ---
>> include/linux/memblock.h | 1 +
>> mm/memblock.c | 22 +++++++++++++++++++++-
>> 2 files changed, 22 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/linux/memblock.h b/include/linux/memblock.h
>> index 50ad19662a32..2f7ef97c0da7 100644
>> --- a/include/linux/memblock.h
>> +++ b/include/linux/memblock.h
>> @@ -125,6 +125,7 @@ int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size);
>> int memblock_mark_mirror(phys_addr_t base, phys_addr_t size);
>> int memblock_mark_nomap(phys_addr_t base, phys_addr_t size);
>> int memblock_clear_nomap(phys_addr_t base, phys_addr_t size);
>> +int memblock_isolate_memory(phys_addr_t base, phys_addr_t size);
>>
>> void memblock_free_all(void);
>> void memblock_free(void *ptr, size_t size);
>> diff --git a/mm/memblock.c b/mm/memblock.c
>> index 25fd0626a9e7..d8cf1c9eccf0 100644
>> --- a/mm/memblock.c
>> +++ b/mm/memblock.c
>> @@ -753,7 +753,8 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type,
>> int idx;
>> struct memblock_region *rgn;
>>
>> - *start_rgn = *end_rgn = 0;
>> + if (start_rgn && end_rgn)
>> + *start_rgn = *end_rgn = 0;
> Generally, it's possible that either start_rgn or end_rgn will be a valid
> pointer and this should be handled here and below.
>
> My preference, though would be to leave memblock_isolate_range() as is and
> have unused start_rgn and end_rgn in memblock_isolate_memory().


Sure, I'll do that then.


>
>>
>> if (!size)
>> return 0;
>> @@ -795,6 +796,9 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type,
>> memblock_get_region_node(rgn),
>> rgn->flags);
>> } else {
>> + if (!end_rgn || !start_rgn)
>> + continue;
>> +
>> /* @rgn is fully contained, record it */
>> if (!*end_rgn)
>> *start_rgn = idx;
>> @@ -805,6 +809,22 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type,
>> return 0;
>> }
>>
>> +/**
>> + * memblock_isolate_memory - isolate given range from memblock.memory
> I think it'd better to use "... range in memblock.memory"


Ok


>
>> + * @base: base of range to isolate
>> + * @size: size of range to isolate
>> + *
>> + * Call memblock_isolate_range on memblock.memory to isolate the given range.
> Please elaborate that isolate means that the range does not share regions
> with other ranges.


Sure, thanks, I'll come up with a v8 tomorrow along with other fixes
(rv32 and arm64 comments that I forgot to remove).

Thanks again,

Alex


>> + *
>> + * Return:
>> + * 0 on success, -errno on failure.
>> + */
>> +
>> +int __init_memblock memblock_isolate_memory(phys_addr_t base, phys_addr_t size)
>> +{
>> + return memblock_isolate_range(&memblock.memory, base, size, NULL, NULL);
>> +}
>> +
>> static int __init_memblock memblock_remove_range(struct memblock_type *type,
>> phys_addr_t base, phys_addr_t size)
>> {
>> --
>> 2.37.2
>>

\
 
 \ /
  Last update: 2023-03-27 00:55    [W:0.465 / U:0.056 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site